Author Topic: Trochoidal Pocket & Profile MOPs plugin (HSM)  (Read 174714 times)

Offline lloydsp

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Re: Trochoidal Pocket & Profile MOPs plugin (HSM)
« Reply #270 on: April 17, 2024, 19:14:33 pm »
Bubba, 0.5 defies the purpose by a TINY margin.  Set it to 0.45 or 0.48 (maybe).  At 0.5, you stand the chance of leaving 'spurs' in your pattern with even a slightly-worn bit.

Lloyd
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Offline Bubba

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Re: Trochoidal Pocket & Profile MOPs plugin (HSM)
« Reply #271 on: April 17, 2024, 19:30:33 pm »
Bubba, 0.5 defies the purpose by a TINY margin.  Set it to 0.45 or 0.48 (maybe).  At 0.5, you stand the chance of leaving 'spurs' in your pattern with even a slightly-worn bit.

Lloyd

Really I'm not that concern with it , nothing sandpaper can't fix it, and when removing material .3" or deeper per pass during roughing operation spurs are not concern for me..
My 2¢

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Offline dave benson

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Re: Trochoidal Pocket & Profile MOPs plugin (HSM)
« Reply #272 on: April 20, 2024, 23:45:52 pm »
Quote
you stand the chance of leaving 'spurs' in your pattern with even a slightly-worn bit

That's the thing Lloyd Troch mops are roughers and need to be followed up with a finisher
If your have your step over aggressive enough there will be scalloping on the walls of the
pocket (this is a good sign you are in the ballpark).

I like the troc mops, they have their superpowers,but they are not a universal panacea for
all pocketing situations, some simple pockets  for example a square with rounded corners
where the radii of the corners are somewhat larger than the diameter of the tool  then a simple
pocket mop would be a better choice, however if the pocket has even just a little more complex geometry
then the troch mops offer a significant speed up in cut time.

Used with a dedicated roughing cutter and one of the feedrate adjusters which rip out the
positioning moves and replaces them with rapids and vary the feedrate to keep the chipload
constant make for fast pocketing between 40 -60 % faster than a standard pocket.

I had a look at the production files and roughly a third of them are troch mops the rest are
plain pockets where the pocket has simple geometry like rounded squares and rectangles with
radii larger than the tool radius.

Dave

Offline Bubba

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Re: Trochoidal Pocket & Profile MOPs plugin (HSM)
« Reply #273 on: April 21, 2024, 21:15:38 pm »
That's the thing Lloyd Troch mops are roughers and need to be followed up with a finisher
*************************************
That's why I always 'rough cut' pocket leaving enough material for profile pass.
My 2¢

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Offline lloydsp

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Re: Trochoidal Pocket & Profile MOPs plugin (HSM)
« Reply #274 on: April 21, 2024, 22:37:50 pm »
With any roughing pass, I leave material for finishing.  But I find that 'cusps', 'spurs', or 'horns' (whatever you might call them)  remaining in any sidewall cause surface finish variations in a finishing pass.  I want uniform surfaces on which to finish, regardless of whether I use ordinary pocketing or trochoidal methods.

Lloyd
"Pyro for Fun and Profit for More Than Fifty Years"

Offline dave benson

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Re: Trochoidal Pocket & Profile MOPs plugin (HSM)
« Reply #275 on: April 22, 2024, 04:45:19 am »
Quote
With any roughing pass, I leave material for finishing. 
But I find that 'cusps', 'spurs', or 'horns' (whatever you might call them)  remaining in any sidewall cause surface finish variations in a finishing pass. 
I want uniform surfaces on which to finish, regardless of whether I use ordinary pocketing or trochoidal methods.

Yes I thought about the profile cut when developing the pocket above, as this was a pocket
on the inside of the machine, I wasn't so worried about the cosmetics, I didn't want to damage
the tool, I looked at the file and I used -0.15 mm roughing clearance + height of the peaks 0.5 mm which cleaned up the pocket
side wall (I could not see any defects or hear it in the cut).
This equates to only 11 percent stepover, so I guess there wasn't enough impulse force caused by the undulating surface to excite the tool.

In the photo you can see a speed run of the troch mops pocket in the file earlier, I didn't run the production file like this as chip clearance
and tool heating were the limiting factor, during the course of developing the pocket (a few months) I added an extra air nozzle and upgraded
the spindle I had no flood cooling and no intention to do so.
In the pic I flooded the pocket as it was developing.
 
Original Standard CB pocket 18 minutes 44 seconds.
Troch mop +FRA                     10 minutes 18 seconds. Speed run

I've left one of the pic's as a full size jpg so that you can zoom in and look at the surface finish.

Dave